Merge pull request #58 from ComponentDriven/kasper/remove-index-signa…

…ture Make sure that index signatures (used in decorators) don't cause unexpected types
ComponentDriven · Nov 14, 2022 · b170e3d · b170e3d
2 parents a8deeb1 + 7052fb8
commit b170e3d
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Showing 2 changed files with 14 additions and 4 deletions.
diff --git a/src/story.test.ts b/src/story.test.ts
@@ -1,5 +1,6 @@
 /* global HTMLElement */
 import { expectTypeOf } from 'expect-type';
+import { Except, SetOptional } from 'type-fest';
 import {
   Renderer,
   Args,
@@ -10,6 +11,7 @@ import {
   LoaderFunction,
   ProjectAnnotations,
   StoryAnnotationsOrFn,
+  StrictArgs,
 } from './story.js';
 
 // NOTE Example of internal type definition for @storybook/<X> (where X is a renderer)
@@ -113,6 +115,10 @@ test('ArgsFromMeta will infer correct args from render/loader/decorators', () =>
   const decorator2: DecoratorFunction<XRenderer, { decoratorArg2: string }> = (Story, { args }) =>
     `${args.decoratorArg2}`;
 
+  const decorator3: DecoratorFunction<XRenderer, Args> = (Story, { args }) => ``;
+
+  const decorator4: DecoratorFunction<XRenderer, StrictArgs> = (Story, { args }) => ``;
+
   const loader: LoaderFunction<XRenderer, { loaderArg: number }> = async ({ args }) => ({
     loader: `${args.loaderArg}`,
   });
@@ -127,7 +133,7 @@ test('ArgsFromMeta will infer correct args from render/loader/decorators', () =>
     component: Button,
     args: { disabled: false },
     render: renderer,
-    decorators: [decorator1, decorator2],
+    decorators: [decorator1, decorator2, decorator3, decorator4],
     loaders: [loader, loader2],
   };
   expectTypeOf<ArgsFromMeta<XRenderer, typeof meta>>().toEqualTypeOf<{

diff --git a/src/story.ts b/src/story.ts
@@ -1,5 +1,5 @@
-import { Simplify, UnionToIntersection } from 'type-fest';
-import { SBType, SBScalarType } from './SBType.js';
+import { RemoveIndexSignature, Simplify, UnionToIntersection } from 'type-fest';
+import { SBScalarType, SBType } from './SBType.js';
 
 export * from './SBType.js';
 export type StoryId = string;
@@ -383,7 +383,11 @@ export type ArgsFromMeta<TRenderer extends Renderer, Meta> = Meta extends {
   loaders?: (infer Loaders)[];
   decorators?: (infer Decorators)[];
 }
-  ? Simplify<RArgs & DecoratorsArgs<TRenderer, Decorators> & LoaderArgs<TRenderer, Loaders>>
+  ? Simplify<
+      RemoveIndexSignature<
+        RArgs & DecoratorsArgs<TRenderer, Decorators> & LoaderArgs<TRenderer, Loaders>
+      >
+    >
   : unknown;
 
 type DecoratorsArgs<TRenderer extends Renderer, Decorators> = UnionToIntersection<